Strain-relief element for footwear articles

ABSTRACT

A strain relief element for a footwear article is provided. The strain relief element is engageable with a portion of a footwear article for engagement with a portion of the foot of a subject, wherein the strain relief element is formed from an elastically deformable material, the strain relief element is sized and provided with a geometry, such that upon engagement with the engagement portion of a foot of a subject, the strain relief element elastically deforms and the internal surface of the strain relief element which engages with the foot of a user substantially conforms to the engagement portion of the surface of the foot of a subject. Footwear including such a strain relief element are also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/484,179, filed Sep. 11, 2014, which is incorporated by reference inits entirety.

BACKGROUND

Technical Field

The present disclosure relates to a strain-relief element for footweararticles, more particularly to a strain-relief element for reducing theincident of blisters and abrasions to the posterior aspect of the heelof a person when wearing a footwear article.

Description of the Related Art

Blisters and abrasions occurring on the foot of a person, in particularon the posterior aspect of heel of a person, have long been anaffliction to people caused by the wearing of footwear articles.

Such an affliction is experienced from persons wearing any footweararticle which contacts the person's foot, particularly the posteriorportion of a person's heel, such footwear articles including sportsshoes, dress shoes, boots, enclosed footwear articles, open sandal typefootwear articles and the like.

Blisters and abrasions on the heel often cause severe pain, and may bedebilitating, thus causing a person to be immobilized or mobilityseverely reduced, due to pain experienced during ambulation and contactof a footwear article with the heel region of a person.

In sports type scenarios, performance of an athlete may be severelycompromised from pain experienced during a sports event. In otherscenarios such as hiking, either recreationally or for commercial ormilitary related activities, the incidence of blisters and abrasionsposes a health and welfare risk, in particular if such ailments occurwhen a person is in a remote area or location in particular wherebythere does not exist the opportunity for evacuation by mechanizedtransport, or in areas of long distance from transport or assistance, ofin areas of rough and awkward terrain.

Untreated blisters and abrasions may further be exacerbated, and uponlesions of the dermis, further abrasion may occur, with moresubcutaneous tissue being exposed, causing immobilization as well as thepotential for infection.

There are several manners of minimizing and treatment of blistersaccording the related art:

(i) Lacing to Minimize Rubbing

In order to prevent rubbing between the heel of a person and theinternal contact surface of a footwear article, is to maintain the heelsecured firmly within the foot wear article, which seeks to minimizeheel abrasion. Such techniques include “lace-lock” as utilized in somesports type footwear articles.

However, such techniques are only applicable to lace up footwear, andsuch footwear generally have lace eyelets further towards the rear ofthe footwear article than typical lace up footwear, thus requiringspecific structural constrains and specific footwear type.

(ii) Taping and Dressings—Protective Layer

A protective layer may be formed in the anterior heel of a person, byadhering a protective layer to the skin, however blisters may occur andfriction may remove or loosen the tape causing stress concentrations andpressure, which may further precipitate blisters. This technique may beused prophylactically, as well as after a blister or abrasion hasformed.

This technique may be used in conjunction with a variety of footweararticle types, however the incidence of blister formation may not beobviated, as use of such a technique may also often be unsightly, inparticular when used by persons wearing sandals and fashion footwear, inparticular when used in conjunction with women's open rear sandals orfootwear.

(iii) Donut-Type Pads

In order to reduce pressure ant the posterior heel portion of a foot ofa person, a “donut” shaped pad may be provided, which id formed from arelatively thick piece of material, typically of a felt type material,having an aperture extending therethrough.

The pad is taped or affixed to the heel of a person, with the apertureof the pad extending over the region of the heel in the region where ablister is likely to occur, or where a blister has occurred. As such,this technique may be used prophylactically, as well as after a blisteror abrasion has formed.

Whilst providing some protection of the posterior heel portion of auser, such a pad may loosen and exacerbate the formation of a blister orabrasion by stress concentration, as well as be unsightly in use.

(iv) Integrally Formed Padded Portion

Another technique of the related art to minimize or obviate theformation of blisters and abrasion of the posterior portion of a heel ofa person, is the incorporation of an integrally formed padded cushioningportion at the superior-posterior portion of a footwear article.

Such padded portions may be formed with a sponge like materialinternally, and are generally formed from the same material from whichthe footwear article is formed.

Whilst providing some comfort and relief and prevent of blisterformation, such padded portions may crack and cause abrasion of theheel, as well as seam portions rubbing or pressing on the heel causingdiscomfort. Further, such padded portions are generally only able to beincorporated in enclosed-type footwear articles, and can be unsightlyand impact unfavorably upon the aesthetic characteristics of thefootwear article.

BRIEF SUMMARY

Embodiments of the present invention aim to provide a strain-reliefelement for footwear articles that overcomes or at least ameliorates atleast some of the deficiencies associated with the related art discussedabove.

In a first aspect, an embodiment of the present invention provides astrain relief element for a footwear article, said strain relief elementbeing engageable with the portion of a footwear article for engagementwith a portion of the foot of a subject, wherein said strain reliefelement is formed from an elastically deformable material, said strainrelief element is sized and provided with a geometry, such that uponengagement with the engagement portion of a foot of a subject, thestrain relief element elastically deforms and the internal surface ofthe strain relief element which engages with the foot of a usersubstantially conforms to the engagement portion of the surface of thefoot of a subject.

The load normal to the engagement portion of the foot imparted to theengagement portion of the foot of the subject is distributed along thestrain relief element so as to reduce point loading to the foot at bonyprominences of the foot of the subject.

Preferably, the strain relief element is formed of a material andfinished so as to provide a reduced friction coefficient and to allowmovement of the strain relief element during ambulation relative to thefoot of the subject, so as to reduce internal shear stresses inducedfrom relative movement between the surface of the foot and bones of thefoot of the subject.

The strain relief element may be located at the anterior contactportion, medial contact portion, lateral contact portion, posteriorcontact portion, or combinations thereof.

Preferably, the strain relief element is engageable with thesuperior-posterior portion of a footwear article for engagement with theposterior heel portion of the foot of a subject, and the strain reliefelement is preferably formed of a material and finished so as to providea reduced friction coefficient and to allow superior and inferiormovement of the strain relief element during ambulation relative to theposterior surface of the heel of the subject, so as to reduce internalshear stresses induced from relative movement between the posteriorsurface of the heel and the calcaneus of the foot of the subject.

Preferably, the strain relief element is formed from an elastomericpolymer.

Preferably, the strain relief element is formed from a silicon basedmaterial, or alternatively the strain relief element is formed from arubber based material.

The strain relief element may further include a tab portion, and whereinsaid tab portion provides a gripping portion for assistance in fitting afootwear article to the foot of a subject.

Preferably, the strain relief element is generally elongate in thelateral direction.

The strain relief element may include rebates for alteration of thestructural properties of the strain relief element.

The strain relief element may further include a recess or a protrudedportion, for the carrying thereon of a marking, wherein said marking maybe a branding or trade mark marking.

In a second aspect, an embodiment of the present invention provides afootwear article comprising a strain relief element according to thefirst aspect.

The footwear article may comprise an upper to which the strain reliefelement is engaged, and a sole member to which the upper is engaged.

The strain relief element may be provided in a color distinct from thecolor of the upper, providing a visual indication of the incorporationof the strain relief element of embodiments of the present inventionwithin the footwear article.

The sole member may be provided in the same or similar color as to thatof the strain relief element, to provide further visual indication ofthe incorporation of the strain relief element of embodiments of thepresent invention within the footwear article.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Preferred embodiments of the present invention will be explained infurther detail below by way of examples and with reference to theaccompanying drawings, in which:

FIG. 1 shows a schematic representation of the heel region of a subject,

FIG. 2 shows a photographic representation of a first embodiment of afootwear article according to the present invention,

FIG. 3 shows a photographic representation of a second embodiment of afootwear article according to the present invention,

FIG. 4 shows a line drawing representation of a further embodiment of afootwear article according to the present invention,

FIG. 5 shows a line drawing representation of another embodiment of afootwear article according to the present invention,

FIG. 6 shows a line drawing representation of yet a further embodimentof a footwear article according to the present invention,

FIG. 7A shows a side view sectional schematic representation of afootwear article with strain relief member according to anotherembodiment of the present invention,

FIG. 7B shows a top view schematic representation of a footwear articlewith strain relief member of FIG. 7A,

FIG. 7C shows a rear view schematic representation of a footwear articlewith strain relief member of FIGS. 7A and 7B,

FIG. 8A shows a schematic representation of an embodiment of a strainrelief element in accordance with the present invention,

FIG. 8B shows a schematic representation of another embodiment of astrain relief element in accordance with the present invention,

FIG. 8C shows a schematic representation of a further embodiment of astrain relief element in accordance with the present invention,

FIG. 8D shows a schematic representation of an alternate embodiment of astrain relief element in accordance with the present invention,

FIG. 9A depicts a first further exemplary embodiment of a lace-upfootwear article in accordance with the present invention,

FIG. 9B depicts a second further exemplary embodiment of a lace-upfootwear article in accordance with the present invention,

FIG. 9C depicts a third further exemplary embodiment of a lace-upfootwear article in accordance with the present invention,

FIG. 10A depicts a first another exemplary embodiment of a slip-onfootwear article in accordance with the present invention,

FIG. 10B depicts a second another exemplary embodiment of a slip-onfootwear article in accordance with the present invention,

FIG. 10C depicts a third another exemplary embodiment of a slip-onfootwear article in accordance with the present invention,

FIG. 10D depicts an example of a boot-type footwear article inaccordance with another embodiment of the present invention,

FIG. 11 depicts an embodiment for a slip-on footwear article whichincludes two strain relief elements in accordance with the presentinvention, and

FIG. 12 shows a rear schematic view of a footwear article having astrain relief element and including a recess or a protruded portion, forthe carrying thereon, such as branding or trade mark marking, inaccordance with other embodiments of the present invention.

DETAILED DESCRIPTION

In order describe the manner in which embodiments of the presentinvention is effected and in contrast to the known art, an understandingof the biomechanics of the heel region of a foot is required, as well asan appreciation of the physiology behind the formation of blisters, incomparison to mechanisms to which the known art is directed.

The formation of blisters has traditionally been thought to be caused bypressure and friction between a footwear article and the foot of aperson, such as between a footwear article and heel posterior portionand pressure, and solutions of the known art are directed to addressingor mitigating the traditionally perceived causes of blister formation.

However, in more recent times, further understanding of biomechanics andtissue mechanics, in particular in the heel region of the foot, hasprovided underlying causes of blister formation.

A blister is trauma of the deep layer of skin cells, which is caused byshear between the skin and the underlying bone structures. Shear occurswhen there is sufficient friction between two objects or portions of anobject, such that when force is applied it moves over the underlyingobject of less resistance. This is distortion within the skin is calledshear. A blister occurs in the case when there is no sliding between theskin surface and the sock/shoe interior, rather thesliding/translational motion occurs relative between the skin and thebones.

Over a period of time, and in particular with lateral foot movementssuch as experienced in tennis, the shear becomes to an abnormal leveland damage is caused, and the damaged area will fill with fluid thuscausing a blister.

By comparison, when there is sliding motion between the sock/shoe andthe skin surface, abrasion which causes damage to only the top layers ofskin occurs, and often results in lesions of the skin and red raw wound.This phenomena is typically observed in poorly fitted or poorlymanufactured footwear articles which allow movement of a foot within thefootwear article.

Whilst blisters such as those that occur on the posterior of the heelhave been traditionally thought be solely caused by the heel moving upand down in the shoe, recent and modern biomechanical and tissueresearch suggests that blisters are actually formed by the calcaneus(i.e., heel bone) moving excessively which causes adjacent skin to beimpinged between the interior of the shoe and the calcaneus. Thisexcessive movement has been suggested to be caused by tight calfmuscles, a bony prominence, or biomechanical related issues.

As such, some solutions of the known art, such as taping, preventabrasions, and do not prevent blisters per se. Thus, taping provides abarrier to the skin to prevent abrasive wear rather than reducing shearwithin adjacent tissue.

Blister management may be complex, as the causes are typicallymulti-factorial, such as foot moisture from sweating, activity level andtype, and shoe fit.

Accordingly, embodiments of the present invention provide a solution tothe cause of both blistering and abrasive wear, which addressesunderlying causes of blister formation as well as causes for abrasivewear.

By way of example and explanation as to how a blister is formed on thefoot of a person, reference is made to the heel portion wherebyreferring to FIG. 1, there is shown a schematic representation of theheel region 10 of a subject, whereby the formation of blisters isdemonstrated diagrammatically. When wearing a footwear article whichengages with the posterior region of the heel of a subject, frictionalforces 6 are present, which are depicted as the tangential and normalcomponents of the frictional force.

During ambulation, the calcaneus 2 may move from small amount to largeamounts as depicted by arrow 4, which causes tissue 3 below the skinsurface to be exposed to shear forces as represented by arrows 8, tocause trauma and the formation of a blister, as described above.

Representations of embodiments of the present invention in theapplication of blister amelioration at the heel portion of a user arenow described with reference to FIGS. 2, 3, 4, 5 and 6, and the mannerin which embodiments of the invention is thereafter described withreference to FIGS. 7A, 7B and 7C.

A first embodiment of the present invention is depicted in FIG. 2,whereby footwear article 20 is shown which includes a strain reliefelement 22 located at the superior-posterior portion of the footweararticle 20. In the present embodiment, the invention is embodied as aballet shoe type footwear article, which includes an upper 24 to whichthe strain relief element 22 is affixed, and which is affixed to a solemember 26. As will be understood, the strain relief element 22 engageswith the heel portion of a subject in use, either directly when no socksor stockings are used, or indirectly when socks and stockings are used.

Referring to FIG. 3, there is shown a second embodiment of the presentinvention whereby footwear article 30 includes a strain relief element32 located at the superior-posterior portion of the footwear article 30,again in which the embodiment of the invention is embodied as a balletshoe type footwear article which includes an upper 34 to which thestrain relief element 32 is affixed, and which is affixed to a solemember 36. Again as will be understood, the strain relief element 32engages with the heel portion of a subject in use, either directly whenno socks or stockings are used.

In the present embodiment, the footwear article 30 further includes aperipheral elastic member 38 which extends around the periphery of theopening in the upper 34 through which a foot is inserted into thefootwear article 30, which functions in cooperation with the strainrelief element 32 so as to provide a tangential hoop strain which causesthe upper to be urged radially inwardly towards the foot of a subject,and provide a fixation mechanism so as to secure the footwear article tothe foot of a subject.

In the present embodiment, the peripheral elastic member is a continuouselastic element which is fixed to the upper 34 adjacent the strainrelief element 32, and which extends around the periphery of the upper34 through a plurality of apertures provided as a series of eyelets,thus providing ease of movement of the peripheral elastic member 38through the apertures so as to provide a more uniform strain and stressin the peripheral elastic member 38 such that a more even load isimparted to the foot of a user along the aperture in the upper, thusproviding increased comfort to the user.

In the present embodiment, the peripheral elastic member 38 is formedfrom a silicon elastic material, which may be provided as a singlefilament structure, or a multi-strand structure.

As will be appreciated by those skilled in the art, the strain reliefelement of the present invention is equally as applicable to a varietyof footwear articles, such as closed shoes, sports shoes, hiking boots,sandals, fashion shoe articles and the like, examples of which aredepicted in reference to FIGS. 4, 5 and 6.

Referring to FIG. 4, there is shown a further embodiment of the presentinvention whereby footwear article 40 whereby the footwear article is alace-up dress shoe. The footwear article includes a strain reliefelement 42 located at the superior-posterior portion of an upper 44 ofthe footwear article 40, with the upper being joined to a sole member46. Again as will be understood, the strain relief element 42 engageswith the heel portion of a subject in use, either directly when no socksor stockings are used, or indirectly when socks and stockings are used.

FIG. 5 depicts another embodiment of the present invention wherebyfootwear article 50 whereby the footwear article 50 is a sandalincluding a rear strap portion 54 which is attached to a sole member 56.The footwear article 50 includes a strain relief element 52 located atthe superior-posterior portion of the rear strap portion 54 of thefootwear article 50. Again as will be understood, the strain reliefelement 52 engages with the heel portion of a subject in use, eitherdirectly when no socks or stockings are used, or indirectly when socksand stockings are used.

As shown in FIG. 6, there is yet another embodiment of the presentinvention whereby footwear article 60 is provided as a high-heeledladies fashion footwear article which includes a closed upper 64 and aheel portion 68 of a sole and a front platform portion 66 of the sole.The footwear article 60 includes a strain relief element 62 located atthe superior-posterior portion of the upper 64 of the footwear article60. Again, as will be understood, the strain relief element 62 engageswith the heel portion of a subject in use, either directly when no socksor stockings are used, or indirectly when socks and stockings are used.

Referring to FIG. 7A, 7B, and 7C, the manner in which exampleembodiments of the present invention operate is depicted and describedschematically. A footwear article 70 is shown for reference whichincludes a sole member 76 and an upper 74 attached to the sole member,with the foot 78 of a subject engaged with the footwear article 70. Astrain relief element 72 is shown which in the present embodiment islocated at the superior posterior aspect of the upper 74.

The strain relief element 72 is formed from an elastic material, such asan elastomeric polymeric material, a silicon based material or a rubberbased material.

The strain relief element 72 and is formed such that the anterior(interior) surface of the strain relief element 72 is relatively smooth,and the strain relief element has a modulus of elasticity and isprovided with a cross sectional area and geometry and peripheral length,so as to provide sufficient compressive hoop stress so as to secure thefootwear article 70 to the foot 78 of the user during ambulation, whilstproviding sufficient movement of the strain relief element relative tothe outer surface of the skin of the user such that:

(i) Upon movement of the calcaneus 73 of the foot 78 internal shearstresses in the region 75 are minimized so as to reduce formation ofblistering, and

(ii) Wear abrasion from the strain relief element 72 on the outersurface of the skin is minimized due to reduced friction and moreuniform load distribution in the radially inward direction from theelastic relief member 72 to the outer skin surface.

This cumulative effect of the strain relief element 72, providesadditional comfort for a user, whilst reducing the incidence ofblistering and abrasion, both which have detrimental effects to a user.

As will be understood by those skilled in the art, suitable sizing andthe geometry of the elastic strain element 72, in combination with themechanical properties of the material from which the elastic strainelement 72 is formed, allows for the provision of sufficient hoop stressso as to sufficiently secure the footwear article to the foot of theuser, whilst utilizing a material so as to provide a suitably lowcoefficient of friction, can minimize internal shear and externalabrasion of the heel of the foot 78 of a user.

The strain relief element, when located at the posterior portion of afootwear article, may, in other embodiments, be provided with a grippingportion for assistance in fitting a footwear article to the foot of asubject.

Referring to FIGS. 8A, 8B, 8C and 8D, there are depicted embodiments ofthe invention with the strain relief element located at the posterior offootwear articles 80A, 80B, 80C and 80D, having an upper 82A, 82B, 82Cand 82D affixed to sole members 84A, 84B, 84C and 84D.

As will be seen, strain relief elements 86A, 86B, 86C and 86D may be ofdifferent shapes and extend partly or fully to the sole members 84A,84B, 84C and 84D, with exemplary embodiments schematically depictedshowing a plurality of strain relief elements 86A, 86B, 86C and 86Dwhich, as will be appreciated by those skilled in the art, may be of anygeometry, shape or size, whilst providing the functional attributes ofthe present invention.

In accordance with the present invention, the strain relief elements86A, 86B, 86C and 86D may be provided of a distinctive color in contrastwith the upper 82A, 82B, 82C and 82D or other components of a footweararticle, which provides for identification that the strain reliefelements 86A, 86B, 86C and 86D are that of the present invention, thusenabling consumers to associate such strain relief elements 86A, 86B,86C and 86D as being those of the present invention visually.Furthermore, in other embodiments, the sole members 84A, 84B, 84C and84D may be of the same or similar color to that of the strain reliefelements 86A, 86B, 86C and 86D, providing for further visualidentification that such footwear articles 80A, 80B, 80C and 80D embodythe strain relief elements 86A, 86B, 86C and 86D of the presentinvention.

As will be appreciated by those skilled in the art, the strain reliefelement may be provided with varying geometry and shape, such as theinclusion of rebates for alteration of the structural properties of thestrain relief element.

Referring to FIGS. 9A, 9B and 9C, there are depicted further exemplaryembodiments of footwear articles 90A, 90B and 90C which include a strainrelief member 95A, 95B and 95C in accordance with the present inventionand located at the posterior of the footwear article. In the presentexemplary embodiments of the invention, the footwear articles arelace-up type footwear articles.

Referring to FIGS. 10A, 10B and 10C, there are depicted other exemplaryembodiments of footwear articles 100A, 100B and 100C which include astrain relief member 105A, 105B and 105C in accordance with the presentinvention. In the present exemplary embodiments of the invention, thefootwear articles are slip-on type footwear articles.

FIG. 10D shows am example of a boot-type footwear article 100D, having astrain relief element 105D in accordance with an embodiment of thepresent invention located at the posterior of the footwear article. Inthis embodiment, the footwear article 100D further includes a strap andbuckle arrangement 107D for securing the footwear article 100D to thefoot of a use.

As shown in FIG. 11, there is an embodiment for a footwear article 110provided as a slip-on footwear article, which includes two strain reliefelements in accordance with the present invention:

a first strain relief element 115 located at the posterior of thefootwear article 110, and

a second strain relief element 119 at the anterior portion of thefootwear article 110 at the location where the foot of a user engageswith the footwear article 110.

Those skilled in the relevant art will appreciate that discomfort to theuser and foot damage may be mitigated at the anterior engagement portionof the foot of a user by the second strain relief element 119, similarlyas described with reference to a strain relief element at the heelportion as depicted by the first strain relief element 115 in thepresent embodiment.

Those skilled in the relevant art will also appreciate that in other oralternate embodiments, footwear article may be provided with the strainrelief member at the anterior contact portion, medial contact portion,lateral contact portion, posterior contact portion, or combinationsthereof.

No limitation may be made to the structure, shape, geometry, size,location, positioning of the strain relief element of the presentinvention, by reference to the embodiments, which are exemplaryembodiments. Further, no inference or limitation may be taken from theexemplary embodiments in respect of the positioning, location, or numberof strain relief elements.

In other embodiments, such as that as exemplified by the schematic rearrepresentation of a footwear article 120 of FIG. 12, the strain reliefelement 122 which is engaged with upper 124 which is engaged with a solemember 126, further may include a recess or a protruded portion, for thecarrying thereon, such as branding or trade mark marking 128. Thebranding or trade marking 128 may be incorporated during themanufacturing process when the strain relief element 122 is formed, andthe branding of trade mark marking may be on the interior aspect of thestrain relief element, the exterior strain relief element, or both theexterior or interior aspect.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

1. A strain relief element for a footwear article, said strain reliefelement being engageable with a portion of a footwear article forengagement with a portion of the foot of a subject, wherein said strainrelief element is formed from an elastically deformable material and isadapted to engage with an engagement portion of the foot of the subject,said strain relief element is sized and provided with a cross sectionalarea and geometry and a peripheral length, such that upon engagementwith the engagement portion of a foot of a subject, the strain reliefelement is adapted to provide sufficient compressive hoop stress so asto secure the footwear article to the foot of the subject duringambulation, elastically deforms and the internal surface of the strainrelief element which engages with the foot of a user is adapted tosubstantially conform to the engagement portion of the surface of thefoot of the subject, load normal to the engagement portion of the footimparted to the engagement portion of the foot of the subject isdistributed along the strain relief element so as to reduce pointloading to the foot at bony prominences of the foot of the subject, andthe strain relief element is formed of a material and finished so as toprovide a reduced friction coefficient and to allow movement of thestrain relief element during ambulation relative to the foot of thesubject, so as to reduce internal shear stresses induced from relativemovement between the surface of the foot and bones of the foot of thesubject.